Wireless communication systems are widely deployed to provide various types of communication such as voice, packet data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, and orthogonal frequency division multiplexing (OFDM) systems. As conditions in the channel vary, it may be necessary to activate certain resources and deactivate others. Similarly, the user may depend on several resources simultaneously. Some devices allow multiple transmitters to operate simultaneously to accomplish these various goals.